I think you're looking at this the wrong way around.
Why don't you start with reading security considerations part of RFC:
IPsec and IKE:
Also, I relized I quoted the TLS RFC not SSL, here's a correction:
prevent message replay or modification attacks, the MAC is computed
from the MAC secret, the sequence number, the message length, the
message contents, and two fixed-character strings
(Section F.2 - part of appendix F)
Edit: you can also read about IKEv2 security considerations! if you think IKEv1 is "not secure".